Chronic rhinosinusitis (CRS) is the most frequently reported chronic disease in the U.S., and its prevalence continues to rise. CRS can be difficult to manage clinically; even surgical intervention often produces only temporary relief. The parent grant (5 R01 AI49235-02) and this application share the long-term goal of identifying the causes and pathophysiologic mechanisms leading to CRS. Towards this goal, the parent grant is analyzing in vitro lymphocyte and eosinophil responses to fungal antigens in conjunction with in vivo analyses of eosinophilic inflammation and antifungal treatment. This application seeks to extend these studies by using two state-of-the-art technologies, cDNA microarrays and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), to screen for pathogenic gene expression in nasal tissue in naturally occurring CRS and in response to Alternaria fungal antigen challenge. Aim 1 is to identify gene transcript changes unique to CRS nasal tissue, cDNA microarrays will be used to measure mRNA transcript levels of 33,000 well-substantiated human genes in naturally occurring and Alternaria-challenged nasal tissue from CRS patients and allergic rhinitis and healthy controls. Aim 2 is to identify protein constituents in nasal secretions using LC-MS/MS. Nasal secretions from CRS patients and healthy controls challenged intranasally with Alternaria antigens or with vehicle alone will be proteolytically digested and fractionated with a biphasic microcapillary column prior to introduction into a mass spectrometer for parent protein identifications. Together, these studies should more comprehensively identify pathologic molecular responses in CRS and clarify the potential involvement of Alternaria in disease etiology. More generally, we will establish the feasibility of applying state-of-the-art mass spectrometry to the analysis of dilute biological fluids - an approach that could importantly contribute to noninvasive analysis of mucosal immune responses. These new molecular approaches should shed light on the mechanisms of CRS and open novel avenues for diagnosis and treatment of this difficult disease. [unreadable] [unreadable]